Oh lordy, what am I doing to myself...but I gotta get into this one.

I started reading the thread 8 or 9 pages ago and decided to jump to the end...and the beat goies on! CG is still a hot subject.

I would have to side with the group that says, CG DOES matter. The couple of points, 'if it weighs nothing, CG don't matter', while true, is not a realistic scenario. Unless you are able to conjur up some serious magic. Not being realistic, I would have to file it under the 'nonsense' heading. 'If it don't have enough power to get off the ground, again, it (CG) don't matter'. See the previous sentence.

When we get into the other stuff, very light, I am of the opinion, as are most people with a real life background in aerodynamics, that CG ALWAYS matters.

There is no question that an extremely forward or aft CG can be compensated for but that does not mean it is flying well. In many cases, an aft CG can be very useful. For instance, in aircraft being used for aerobatics an aft CG, say 35% of MAC (mean aerodynaic chord), allows maneuvers that would not be possible with a more forward CG. But place that CG in that same airplane at 100% of MAC and I suggest it would simply be unable to fly. At best, given enough runway and speed, it attain enough of a nose up attitude to flop into the ground inverted.

Conversely place the CG at 0% MAC, it'd be a ground loving missle.

Given sufficient power and angle of attack, a CG at 0% could be made to fly but a positive angle of attack effectively moves the CG rearward. And 'sufficient power' most likely would entail a power to weight ratio of 1:1 or better.

Yep, the Buick trunk lid, along with barn doors an other items, will fly with enough power. But I prefer to make the distinction between 'flying' and 'flying well'.

There used to be, and may still be out there yet, the idea that tail heavy aircraft fly faster at the same power setting and weight since when trimming nose down to compensate for the aft CG, the horizontal stab is now generating lift and more engine power can be converted to speed. This may be why so many unlimited racers in the 40's and 50's experienced low altitude accelerated stall/snaps when rounding the pylons. Easy to overcontrol the pitch.

Say what you will about thinking outside the box, expanding your horizons, seeing things in a new light, etc., but I will continue to advocate a good flying airplane and CG control is one of the major issues to that end.

I do enjoy the the electric foamies with very light wing loading and if you are flying in a confined space and hanging on the prop with an angle of attack of +45 degrees, I'll agree the CG is of little consequence. But then I would suggest you are not really 'flying'.

That's my story and I'm stickin' to it!

Joe
AMA L166